Safety lock for doors



Feb. 24, 1959 F I G. l

s. J. SAGE ET AL SAFETY LOCK FOR DOORS Filed May 25,

\ INVENTOR.

W y BY F M ATTORN EV United ates Patent SAFETY LOCK FOR DOORS Stanley J.Sage, Brookline, and Eugene H. Dana, Canton, Mass.

Application May 25, 1956, Serial No. 587,272

1 Claim. (Cl. 292-347) This invention relates to safety locking devicesfor door latch mechanisms, reference being had particularly to thepush-button type locking devices of the class commonly employed inautomobile doors wherein a push-button is secured in threadedrelationship about an operating rod which projects vertically throughthe window frame of the automobile door and which constitutes a part ofan actuating linkage for locking the main door latch mechanism.

As is well known, depressing the push-button serves to lock the latchmechanism and prevent accidental opening of the door, but thepush-button is, of course, readily pulled up into a disengaged positionand, from the standpoint of safeguarding children inside an automobile,is not a satisfactory safety lock. Various safety locking devices havebeen proposed to avoid the hazard involved but none of these, so far aswe are aware, has been adopted commercially and there continues to be inpres ent usage almost universally in car door'latch construcw tions thesimple push-button type of device described above.

It is a general object of the invention to improve pushbutton typelocking devices for door latch mechanisms and to devise a special safetypush-button construction which can be employed to take the place of astandard type of push-button. It is a further object of the invention tocombine in a replacement push-button'member effective safety lockingfeatures which are very conveniently placed in. efiect and whichnevertheless require a combination of unlocking movements calculated togreatly reduce the danger of accidental release by children.

These and other objects and novel features may be more clearlyunderstood and appreciated from the following description of preferredembodiments of the invention shown in the accompanying drawings, inwhich:

Fig. 1 is a view in cross-section of a door latch pushbuttonconstruction designed to include a resiliently sup ported component;

Fig. 2 is a view in cross-section of the structure shown in Fig. 1illustrating this structure in a displaced locking position; and

Fig. 3 is a perspective view showing in detail one of the componentparts of the push-button construction shownin Figs. 1 and 2.

In the structure shown in these drawings, numeral 2b indicatesfragmentarily a door, such as an automobile door, for example, in whichthere is provided a window frame section 4b. Numeral 6b denotes anoperating rod forming a part of an operating linkage for locking a doorlatch mechanism of the class commonly installed in automobile doors. I

The actual door latch mechanism which is to be safety j 2,874,988Patented Feb. 24, 1959 "ice locked has not been shown in detail in thedrawings, as it is believed that the illustration of the operating rod6b is sufliciently representative of such a well-known structure. As iscustomary in most such door latch installations, the operating rod 6bextends upwardly through an opening 8b formed in the window frame 4b ina position such that it may conveniently receive a threaded push-buttonthereon.

Our present invention is based on the novel concept of substituting forthe conventional form of one-piece push-button ordinarily used, aspecial safety push-button construction which includes two separatesections capable of being secured to the operating rod of a door latchmechanism in such a manner that each section may be independentlysupported on the rod whereby one section is laterally displaceable withrespect to the other section.

In accordance with a further aspect of the invention, we provide meansfor displacing one of the sections into a position in which it may beengage with an underside of the window frame 4b and, by solidly securingthis section to the operating rod, it is possible to effectively lockthe door latch mechanism against accidental release.

Considering this safety push-button construction more in detail,attention is first directed to the form of the invention illustrated inFigs. 1 and 2.

At its upper end, the tubular member 30 is formed with a flanged head 32which is adapted in one position to seat against a shouldered portion 34of a recess 36 in the top of the push-button section 10b. A spring 38 islocated between the flange portion 32 and the shouldered portion 34 andnormally seeks to hold the sleeve in the position shown in Fig. 1.However, the push-button section 1% may be raised upwardly against theaction of the spring for a short distance and may then be turned aboutits vertical axis. Rotative movement of the push-button section 10bcauses disp1acement of a shouldered section 40 with respect to acomplementary shouldered portion 42 formed on the pushbutton section12b. This rotative movement, having been carried out with thepush-button sections in an extended position, a lateral displacementtakes place and the lower push-button section is moved into lockingengagement with the sill 4b and, at the same time, the shoulderedportions 40 and 42 resist rotative movement of the section 10b. Torelease this holding action of the shouldered and spring-held sleeve, itis necessary to lift the push-button section 10b upwardly and turn it inone direction so that the shouldered portions may be moved into acomplementary seated position.

It will be evident from the foregoing description that we have provideda positive and effective safety lock which is particularly suited foruse where it is desired to avoid accidental release by children. Thecomponent parts are conveniently constructed and assembled on theoperating rod of standard type and require no changes in the door orlatch mechanism.

While we have shown and described preferred embodiments of theinvention, it should be understood that various other changes andmodifications may be employed within the scope of the appended claim.

Having thus described our invention, what we claim is:

,A push-button construction for use with the operating rod of a doorlatch mechanism comprising upper and lower push-button sections, saidlower section having a tubular extension eceentrically disposed andsecured therein, said extension being fixed to the operating rod,

, 3 4 a the nbperpnshr'button section having the tubular exten-References Cited in the file of this patent sion resiliently and glidably enppqyied therein, apei said v UNITED STATES PATENTS upper andlower push-button seetlons havmg ad acent surfaces relieved to formcomplementary engaging shoul- $67524 Share Sept 1875 ders rotatable intoand out of locking engagement with 5 Bauniberger Sept 1881 one another.1,796,748 COquflle Mar. 17, 1931 2,582,237 Dall Ian. 15, 1952 2,779,619Taylor Jan. 29, 1957 2,788,235 Gilmouru; Apr. 9, 1957

